Carson Palmer announces retirement after 15 years in the NFL

Palmer played for 15 seasons in the NFL, including stints with the Bengals, Raiders, and Cardinals.

It marks yet another big change to the Cardinals franchise going into 2018, having already lost head coach Bruce Arians to retirement earlier in the week.

Carson Palmer has announced his retirement from the NFL in an open letter after fifteen seasons in the league.

"For 15 years I have been lucky enough to play quarterback in the NFL and it has been the most incredible experience of my life," Palmer wrote. "There wasn't one second that I took it for granted or failed to appreciate what a tremendous privilege it is."

Palmer entered the league as the first overall pick of the 2003 NFL Draft after winning the Heisman Trophy as quarterback for the USC Trojans. He would lead the Bengals for eight years, making the Pro Bowl twice before a falling out with the team led to his first retirement after the 2010 season.

The next year, he would begin a brief stint with the Oakland Raiders before joining the Arizona Cardinals for what would be a fairly successful final chapter of his career. In 2015, at the age of 35, Palmer had the best season of his career, throwing for 4,671 yards, 35 touchdowns, and just 11 interceptions, and leading the Cardinals to their first 13-win season in franchise history before eventually losing to the Panthers in the NFC Championship.